Regarding the prevention of electronic devices from EMI, the most common idea is to figure out a way for conducting the EMI to the ground. There are mainly two types of the prior art technologies for carrying out such an idea. As to one of the types, the EMI of the device is first conducted to a printed circuit board of an electronic product, and then leaded by a predetermined path for grounding on the circuit of the board to electronically connect with a grounding system such as a screw hole. Following the engagement of the screw hole with a metal frame for grounding in the electronic product, the EMI of the device can be conducted to the ground. However, the path for grounding on the circuit is usually long and tortuous in order to accommodate others paths used for different functions in the electronic product, and therefore tends to cause the Antenna Effect. Besides, it might even induce more seriously double or triple EMI effects resulted from surrounding the path for grounding with so many sophisticated metal lines or other electronic components.
The other type of the prior art technology provides a metal-shelled plug connected with the grounding signal of the electronic device, wherein the EMI of the device can be grounded by directly setting the metal shell of the plug to contact with the metal frame devoid of passing through the printed circuit board of the electronic product. Although the metal-shelled plug improves the disadvantages of the aforementioned prior art, it still suffers from the higher cost due to the difficulty of manufacturing, particularly to those with complicated wire structures. For instance, as considering the cost, S Terminals with plastic shell are more popular than those with metal shell, even through the later has been invented for many years. Therefore, the aforementioned prior art is still adopted for reducing EMI within most of the electronic products.
Accordingly, there is a need to provide an electronic apparatus having advantages of shorting a grounding path without passing around such sophisticated circuit on the printed circuit board, disusing the more expensive metal-shelled plug for grounding, and effectively reducing the EMI of the electronic device as well.